JPS6335655B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a compound obtained by polymerizing isocyanurate using hexamethylene diisocyanate as a polyol adduct. Hexamethylene diisocyanate (HDI)
) has traditionally been considered to be extremely difficult to polymerize into isocyanurate. In general, many catalysts are known for isocyanurate polymerization of organic isocyanates. For example, tertiary amines, tertiary phosphine, metal salts of acetylacetone, alkali metal salts of organic acids, etc. are effective, as disclosed in Japanese Patent Publication No. 40-5838 and Japanese Unexamined Patent Publication No. 52/1972.
-69497 and JP-A-54-32490. However, although these catalysts are effective for aromatic isocyanates, they are very selective for aliphatic isocyanates, and catalysts that are effective for aromatic isocyanates are not effective for aliphatic isocyanates. There are many things. Among aliphatic isocyanates, the isocyanurate polymerization of HDI is particularly difficult, and the obtained polymer has low compatibility with other resins and solvents, so it has not yet been put to practical use. The present inventors have discovered a method for efficiently producing HDI polymers having isocyanurate groups by overcoming these drawbacks. The present invention is a method for producing an isocyanurate group-containing polymer by polymerizing 60% by weight or less of the total isocyanate groups of the HDI polyol adduct using a specific catalyst. Use a partner polyol with a molecular weight of 3000 or less and a functionality of 2 to 3, contribute 15% by weight or less of the total HDI isocyanate groups to the polyol adduct formation, and add an isocyanurate catalyst of 0.001 weight% to the HDI polyol adduct. % to 0.25% by weight, and 0.5% by weight or less of a co-catalyst, and the isocyanurate-forming reaction is carried out at 100°C or lower. In the urethanization reaction to produce the HDI polyol adduct in the present invention, a polyol is added to HDI by a conventional method, and the reaction temperature is 100°C or less, preferably 70 to 90°C, and about 2
This can be achieved by carrying out a time reaction. If the reaction temperature is higher than 100°C, the product may be colored or side reactions may occur, which is not preferable. It has been found that by converting a portion of HDI into urethane using a polyol, it becomes easier to convert it into isocyanurate, and at the same time, the resulting polymer has even better compatibility with other resins and solvents. As the polyol for urethanization that can be used in the present invention, di- to trifunctional polyols having a molecular weight of 3000 or less are suitable. Examples of diols include ethylene glycol, diethylene glycol, 1.3 butanediol (hereinafter abbreviated as 1.3BG), 1.4 butanediol, propylene glycol, dipropylene glycol, neopentyl glycol, 1.6 hexane glycol (hereinafter abbreviated as 1.6HG), etc. Examples include alcohols, polyester polyols, and polyether polyols. Examples of triols include trihydric alcohols such as glycerin, trimethylolethane, and trimethylolpropane, polyester polyols, and polyether polyols. Polyols can also be used in blend systems of these. This urethane conversion rate is desirably 15% or less based on the total isocyanate. When it becomes more than 15% by weight,
The characteristics of the isocyanurated bond formed thereafter cannot be fully exploited. The urethanation reaction and the isocyanuration reaction described later can be carried out in the presence or absence of a solvent. When using a solvent, use one that is inert to isocyanate groups and that dissolves the produced polymer, such as ethyl acetate, butyl acetate, acetic acid esters such as cellosolve acetate (hereinafter abbreviated as cello acetate), toluene, xylene, etc. All solvents that can generally be used in urethane reactions, such as aromatic hydrocarbons, can be used. In the isocyanurate polymerization method, potassium or sodium salts of certain fatty acids are effective as catalysts, either alone or in combination. Generally, phosphines, which have been conventionally known as isocyanurate catalysts, are not preferred because they cause a dimerization reaction at the same time as the isocyanurate reaction. The produced dimer is unstable and easily dissociates, so that the excellent properties of the isocyanurate ring of the polymer cannot be fully exhibited. In addition to these catalysts, a co-catalyst may be used if necessary. Examples of co-catalysts include phenolic hydroxy compounds such as phenol, cresol, and trimethylphenol, alcoholic hydroxy compounds such as ethanol, cyclohexanol, and ethylene glycol, and tertiary amines such as triethylamine, metherpyridine, and benzyldimethylamine. There is. The amount of catalyst used varies depending on the activity of the catalyst, and the amount of catalyst can also be reduced by using a co-catalyst. The amount of catalyst is based on the HDI polyol adduct.
0.001% to 0.25% by weight, preferably 0.001% to 0.15% by weight, the cocatalyst may be up to 0.5% by weight, preferably up to 0.3% by weight based on the HDI polyol adduct. The isocyanurate conversion polymerization rate is preferably 60% by weight or less based on the total isocyanate. Since the activities of the two isocyanate groups of HDI are almost equal, in an isocyanurate reaction using a conventional method, free HDI gels until it reaches 1% by weight or less. Therefore, a method should be used in which partial polymerization is stopped to prevent gelation, and then unreacted HDI is removed by a known method such as distillation or extraction. The present inventors have found that it is effective to suppress this partial polymerization rate to 60% by weight or less based on the total isocyanate groups. In the isocyanurate formation reaction, it has been found that the effect of this partial urethanization is remarkable, especially when the reaction is carried out in the absence of a solvent. If this method is not used, that is, if HDI is isocyanurated and polymerized as it is, compatibility between the isocyanurated polymer of HDI and HDI monomer is not good, and turbidity may occur in a solvent-free solution. . However, by converting a portion of HDI into urethane, this urethane has good solubility in both HDI monomers and isocyanurate polymers, so even when polymerized in a solvent-free environment, a clear liquid is produced without turbidity. I found out what I could get. Another great advantage is that by partially urethanizing, the formation of polyfunctional polymers due to partial polymerization can be reduced. Furthermore, isocyanurate polymerization of HDI is extremely difficult to occur in the absence of a solvent, but by urethanizing a portion of HDI, the urethane group plays a role as a promoter, making the isocyanurate reaction extremely easy. was found to progress. The isocyanurate polymerization reaction has a reaction temperature of 100℃.
℃ or lower, preferably 35 to 70℃. If the amount of catalyst is large or the reaction temperature exceeds 100°C, polymers of isocyanurate compounds or allophanate compounds are likely to be formed, which may reduce compatibility or cause gelation, resulting in discoloration. It can also cause The decrease in NCO content as the isocyanurate progresses can be measured by titrimetric analysis, so the reaction can be stopped when the desired NCO content is reached. The NCO content and viscosity of the isocyanurated HDI polymer can be freely changed depending on the NCO content at the time of termination of the reaction. The isocyanurate formation of HDI according to the present invention has advantages such as a small amount of catalyst and the ability to react at low temperature in a short time. As a terminator, commonly used strong acids,
For example, this can be achieved using phosphoric acid, sulfuric acid, etc. The isocyanurate group-containing polymer obtained by the present invention has a free HDI of 1% or less, while
Because there are fewer polymers due to side reactions, etc., compared to conventional
Compared to HDI derivatives, it has the advantage of lower viscosity and higher NCO content. Although this polymer can be manufactured even if it contains a solvent, the same quality of product can be obtained even without a solvent, so it is widely useful as a raw material for paints, adhesives, elastomers, plastic foams, etc., and is highly resistant. Demonstrates excellent performance in yellowing, heat resistance, water resistance, weather resistance, etc. Next, the present invention will be explained in more detail with reference to Examples. In the examples, parts refer to parts by weight. Examples 1, 2, 4, 5, 9, 10 500ml equipped with thermometer, stirrer and nitrogen sealed tube
Contains a four-necked glass flask with a sliding lid. HDI and polyol were added in a ratio of 1 part, the air in the flask was replaced with nitrogen, and the mixture was heated while stirring. 1.Heat to the reaction temperature of 1, and at the same temperature. 1 for a predetermined period of time.
NCO content was measured. The reaction solution was a colorless and transparent liquid. Next is the table. 1
The isocyanurate reaction was carried out by adding a catalyst and a co-catalyst at a ratio of . Table 1 is shown in this reaction solution. Add a terminator as in step 1, stir for 1 hour at the reaction temperature, and then release using a molecular distillation device.
HDI was removed. The obtained liquid is pale yellow and transparent, and its NCO content is
Viscosity and free HDI are shown. Shown in 1. In the infrared absorption spectrum of this liquid, strong absorption specific to the isocyanurate ring was observed at 1680 cm ^-1 , and no absorption at 1780 cm ^-1 specific to the dimer was observed. Examples 3 and 6 HDI, polyol and catalyst are listed below. The reaction was carried out in the same manner as in Example 1. Table the results. Shown in 1. Examples 7 and 8 HDI, solvent, polyol, catalyst, and cocatalyst (excluding Example 8) are shown in the table. The reaction was carried out in the same manner as in Example 1. Table the results. Shown in 1. Example 11 Table of HDI, polyol, catalyst and co-catalyst. 2
Example. The reaction was carried out in the same manner as in 1. Table the results. Shown in 2. Comparative Example 1 An HDI polyol adduct was produced in the same manner as in Example 1, except that the isocyanurate catalyst and cocatalyst were changed as shown in Table 1. Use 0.4% and 0.5% as shown in 1, 60℃
The isocyanurate reaction was started. The reaction solution showed a rapid temperature rise, and although it was immediately cooled to 60°C, it became light brown and had a high viscosity, making it impossible to continue the reaction. Infrared analysis revealed that 75% of all isocyanate groups were consumed in isocyanurate formation. Comparative Example 2 The HDI polyol adduct was produced in the same manner as in Example 2, and the isocyanurate formation was carried out using the same amount of catalyst and cocatalyst as in Example 2, and only at a high reaction temperature of 120°C. The reaction became noticeably brown and the viscosity and temperature increased rapidly, making it impossible to continue the reaction. Infrared analysis revealed that 70% of all isocyanate groups were consumed in isocyanurate formation. Comparative Example 3 HDI, polyol, catalyst and co-catalyst are shown below. 2
Example. The reaction was carried out in the same manner as in 1. Table the results. Shown in 2. A comparative test of paint is shown below. 3 (about isocyanurates), Table. 4 (About formulation), Table. 5 (Regarding comparative test results). Comparative Example 4 HDI, polyol, catalyst and co-catalyst are shown in the table. 2
Example. The reaction was carried out in the same manner as in 1. The reaction solution turned into a gel with a pale yellow appearance. Comparative Example 5 HDI, polyol (20% of total isocyanate group equivalent), catalyst, and cocatalyst are shown in the table. Example. The reaction was carried out in the same manner as in 1. Table the results. Shown in 2. A comparative test of paint is shown below. 3. Table. 4. Table. 5
It was shown to. Comparative Example 6 The generation of HDI polyol adduct, the amount of isocyanurate catalyst, co-catalyst, etc. used were the same as in Example 3, and the reaction was conducted at the same temperature for 15 hours, resulting in a pale yellow color and high viscosity, and the reaction continued. I couldn't. As a result of infrared analysis, 65% of the total isocyanate groups
was found to be consumed in isocyanurate formation. Compatibility Test 1 Synthesis of Comparative Samples Comparative Examples 7, 8 and 9 are shown below. This is HDI
is directly polymerized into isocyanurate without urethanization. Comparative Examples 7 and 8 HDI and an isocyanurate catalyst were placed in a flask (same as in Example 1). The air in the flask was replaced with nitrogen, and the mixture was poured with stirring. 1
Heat to the reaction temperature shown in Table. After reaction for a specified time in step 1
Table 1 shows the results of measuring NCO content. The value was as shown in 1. The reaction solution was pale yellow and transparent. Phosphoric acid was added to this reaction solution as a terminating agent, and after stirring at the reaction temperature for 1 hour, it was released using a molecular distillation device.
HDI was removed. Table the results. Shown in 1. Comparative Example 9 HDI, solvent, isocyanurate catalyst and co-catalyst are shown below. The reaction was carried out in the same manner as in Comparative Example 8. Table the results. Shown in 1. 2 Compatibility Test A compatibility test was conducted on the polymers obtained in Examples 1 to 11 and Comparative Examples 3, 5, 7 to 9 with Nipporan 800 (manufactured by Nippon Polyurethane) and Epicote 1001 (Ciel Chemicals). Test method Polyol (Nituporan 800, Epicote 1001)
is ethyl acetate: butyl acetate: toluene: vinegar cello =
Using a 1:1:1:1 (weight ratio) mixed solvent with a solid content of 40%, the
NCO the polymer and polyol using a ml beaker:
Blended at OH=1:1. Judgment by naked eye. Results Coating film test 1 Preparation of polyol component liquid Table 1 shows the specified amounts of polyol, pigment, solvent, etc. A polyol component liquid was prepared by blending the components in the ratio shown in 4 using a paint conditioner. 2 Test List the isocyanurate and polyol components. 4
Mix in the proportions shown in Table. The mixture was diluted with a diluting solvent in the proportions shown in 3, and sprayed onto a mild steel plate (Bonderite No. 1077) to a coating thickness of 30 μm. After standing at 25° C. for 7 days, a coating test was conducted. Table the results. 5. Examples 1 to 10 were transparent, but Comparative Examples 7 to 9
became cloudy. table. See 1. Example 11 and Comparative Examples 3 and 5 were transparent.
table. See 2.

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Claims (1)

[Scope of Claims] 1. A method for producing an isocyanurate group-containing polymer by polymerizing 60% by weight or less of the total isocyanate groups of a hexamethylene diisocyanate polyol adduct, comprising: Molecular weight as partner polyol of hexamethylene diisocyanate
3000 or less, with a functionality of 2 to 3, contributing 15% by weight or less of the total isocyanate groups of hexamethylene diisocyanate to the polyol adduct formation, and using an isocyanurate catalyst of 0.001% to the hexamethylene diisocyanate polyol adduct. 1. A method for producing an isocyanurate group-containing polymer, which comprises carrying out an isocyanurate reaction at 100° C. or lower using a cocatalyst of 0.5% by weight or less and a cocatalyst of 0.25% by weight or less.